U.S. Pat. No. 4,793,861 discloses products that have a cement base containing alkaline-resistant glass fibers, metakaolin and acrylic or styrene-butadiene latex polymers. Such products exhibit excellent resistance to aging. The purpose of the polymer component is to promote curing of the product and to further improve the moduli of rupture, i.e., the breaking stress, which may be attained with such products relative to products not including such a polymer. In certain cases, however, it is difficult to apply a mixture of the type described above, e.g., when spraying on a vertical wall, but applicant has now developed a novel process for producing mixtures which permit such modes of application.